The present invention relates generally to portable canopies, tents and shade structures.
There are a variety of tent and canopy constructions utilizing a structural framework across which a removable cover is placed, the particular features of the construction being dependent upon the use to which the construction is directed. The roof covers which have been utilized in such structures are generally formed of a material which is intended to completely interdict moisture (i.e., rain and dew), and is therefore generally inflexible. However, when subjected to frequent use, such fabrics are subject to stretching, and therefore frequently form sags or pockets into which water may collect.
Recently, there have been a class of portable shade structures manufactured by the Gale Group, Inc. (formerly Weathashade Corporation) under the trademarks PORTASHADE, GAZEBO and PAVILION. These portable shade structures are characterized by a knockdown structural framework and a roof cover of a stretchable woven shade cloth which is not designed to prevent the flow of water, but is designed to interdict a majority of sunlight. In order to stretch these woven fabric shade cloth covers, the cover typically is hooked at the peripheral hem to one of a number of vertical supports which form a part of the knockdown structural framework.
There are some uses for portable shade structures that dictate a need for a generally inflexible material such as that used in the prior art for tents and canopies, but which avoid roof sag and pocketing. Some of such uses also dictate the need for a portable shade structure which may be taken down and set up frequently without incurring the risk of such sagging and pocketing; for example, such uses include portable display shelters for fleamarkets, outdoor exhibits at weekend art festivals and similar events.
Prior art of interest is disclosed in the following U.S. Pat. Nos. 4,677,999 to Cannon et al; 3,874,396 to Kirkham; 3,960,161 to Norman; 4,229,914 to Lucas; 4,793,371 to O'Ferrell et al; 1,792,670 to Wickstrum; 2,535,618 to Williams and 3,441,037 to Transean. See also, Australian Patent 3297/26; German Patent 23 39 320; French Patent 2,430,531; U.K. Patent 277,443; and South African Patent 86/4383.